41 research outputs found
Type-I superconductivity in AlRe
While the pure elements tend to exhibit Type-I rather than Type-II
superconductivity, nearly all compound superconductors are Type-II, with only a
few known exceptions. We report single crystal growth and physical
characterization of the rhenium aluminide AlRe, which we conclude is a
Type-I superconductor based on magnetization, ac-susceptibility, and
specific-heat measurements. This detection of superconductivity, despite the
strong similarity of AlRe to a family of W and Mo aluminides that do not
superconduct, suggests that these aluminides are an ideal testbed for
identifying the relative importance of valence electron count and inversion
symmetry in determining whether a material will superconduct.Comment: 9 pages, 7 figures, CIF file as ancillar
A revisit of superconductivity in 4-TaSSe single crystals
Previous investigations of 4-TaSSe mainly focused on the
direct competition between superconductivity and charge density wave (CDW).
However, the superconductivity itself, although has been prominently enhanced
by isovalent Se substitution, has not been adequately investigated. Here, we
performed a detailed electrical transport measurement down to 0.1 K on a series
of 4-TaSSe single crystals. A systematic fitting of the
temperature-dependent resistance demonstrates that the decreased Debye
temperatures () and higher electron-phonon coupling constants
() at the optimal Se doping content raise the superconducting
transition temperature (). Additionally, we discovered that the
incorporation of Se diminishes the degree of anisotropy of the
superconductivity in the highly layered structure. More prominently, a
comprehensive analysis of the vortex liquid phase region reveals that the
optimally doped sample deviates from the canonical 2D Tinkham prediction but
favors a linear trend with the variation of the external magnetic field. These
findings emphasize the importance of interlayer interaction in this segregated
superconducting-Mott-insulating system.Comment: 11 pages, 5 figure
Pressure-induced superconductivity in charge-density-wave compound LaTe2-xSbx (x=0 and 0.4)
Here, we have grown single crystals of LaTe2-xSbx (x=0 and 0.4) with
continuously adjustable CDW. High-pressure x-ray diffraction show LaTe2 does
not undergo phase transition and keep robust below 40 GPa. In-situ
high-pressure electrical measurements show LaTe2-xSbx undergo
semiconductor-metal-superconductivity transition at 4.6 and 2.5 GPa,
respectively. With the doping of Sb, the highest Tc increases from 4.6 to 6.5
K. Theoretical calculations reveal that the CDW has been completely suppressed
and the calculated Tc is about 2.97 K at 4.5 GPa, consistent with the measured
value. Then, the pressure-induced superconductivity in LaTe2-xSbx can be
explained in the framework of the BCS theory.Comment: 11 pages, 5 figure